Cobalt compounds acetylacetonate

For cobalt phthalocyanines (PcCo, PcCoX), besides the most common method starting with phthalonitrile and cobalt(II) chloride in ethylene glycol, 130-277 279 some other methods have been employed. Other cobalt compounds used are cobalt(II) acetate127 or acetylacetonate.279 Besides using solvents like 2-ethoxyethanol279 and 2-(dimethylamino)ethanol,121 the reaction has also been performed without solvent.137,262 The central metal may exhibit the oxidation states +11 (PcCo) and + III (PcCoX).279... 

CHROMIUM TRIOXIDE-PYRIDINE COMPLEX, preparation in situ, 55, 84 Chrysene, 58,15, 16 fzans-Cinnamaldehyde, 57, 85 Cinnamaldehyde dimethylacetal, 57, 84 Cinnamyl alcohol, 56,105 58, 9 2-Cinnamylthio-2-thiazoline, 56, 82 Citric acid, 58,43 Citronellal, 58, 107, 112 Cleavage of methyl ethers with iodotri-methylsilane, 59, 35 Cobalt(II) acetylacetonate, 57, 13 Conjugate addition of aryl aldehydes, 59, 53 Copper (I) bromide, 58, 52, 54, 56 59,123 COPPER CATALYZED ARYLATION OF /3-DlCARBONYL COMPOUNDS, 58, 52 Copper (I) chloride, 57, 34 Copper (II) chloride, 56, 10 Copper(I) iodide, 55, 105, 123, 124 Copper(I) oxide, 59, 206 Copper(ll) oxide, 56, 10 Copper salts of carboxylic acids, 59, 127 Copper(l) thiophenoxide, 55, 123 59, 210 Copper(l) trifluoromethanesulfonate, 59, 202... 

Decomposition kinetics of cobalt(III) acetylacetonate. The decomposition of cobalt(III) acetylacetonate In various media has been studied by following the change In concentration by means of ultraviolet spectrophotometry. The following facts have been established concerning the decomposition of this compound at 50 C ... 

Another supporting evidence for complex formation as a prerequisite to synergism was obtained from the study of the catalysis of phenyl isocyanate-butanol reaction by soluble organic cobalt compounds in presence and absence of DABCO catalyst. The results obtained are presented in Figures 4 and 5. It is evident that the combination of DABCO catalyst with divalent cobalt compounds shows synergistic effects while the trivalent cobalt acetylacetonate shows relatively low activity. The explanation of these observations is the structure of these compounds. 

Cobalt(III) acetylacetonate has been prepared by the reaction of an aqueous suspension of cobalt(III) oxide with acetylacetone and by the oxidation of an aqueous solution of a cobalt(II) salt with hypochlorite ion in the presence of acetylacetone.1-3 The present synthesis may be considered a modification of these in that it involves oxidation of a cobalt (II) compound in the presence of acetylacetone. 

Certain organometallic compounds can be used to mediate controlled/ living radical polymerization due to their liable and reversibly-cleavable metal-carbon bond. For example, organocobalt complex, such as tetramesitylporphyrinato Co(II) complex [Co(TMP)], has been used to mediate the CRP of aciylates. The first successful cobalt-mediated CRP of VAc was reported by Debuigne and Jerome et. al. using cobalt(ll) acetylacetonate complex Co(acac)2 (Scheme 2) ... 

Monodisperse CoFe204 nanocrystals are synthesized by using a combination of a nonhydrolytic process and seed-mediated growth [227]. The general strategy is using coordination compounds of iron(III) and cobalt(II) acetylacetonate, Fe(acac)3 and Co(acac)2, as precursors in a nonhydrolytic process to synthesize CoFe204 spherical nanocrystals with a mean diameter of ca. 5 nm. Such nanocrystals then serve as seeds... 

A pressure bottle charged with fruns-stilbene and chromium (III) acetylacetonate as the transition metal compound, evacuated, flushed with N2, pressured with Hg, Ng-flushed toluene and triisobutylaluminum as the catalyst alkylation agent in n-heptane injected by syringe, the resulting soln. stirred 20 hrs. at room temp, and 3.7 atm. bibenzyl. Y 78%. F. e., also with the more active catalysts prepared from iron (III) and cobalt (III) acetylacetonates, s. M. F. Sloan, A. S. Matlack, and D. S. Breslow, Am. Soc. 85, 4014 (1963). 

Chemical ingenuity in using the properties of the elements and their compounds has allowed analyses to be carried out by processes analogous to the generation of hydrides. Osmium tetroxide is very volatile and can be formed easily by oxidation of osmium compounds. Some metals form volatile acetylacetonates (acac), such as iron, zinc, cobalt, chromium, and manganese (Figure 15.4). Iodides can be oxidized easily to iodine (another volatile element in itself), and carbonates or bicarbonates can be examined as COj after reaction with acid. 

Cobalt(II) can be separated from cobalt(III) as the acetylacetonate (acac) compounds by extraction of the ben2ene soluble cobalt(Ill) salt (14). Magnesium hydroxide has been used to selectively adsorb cobalt(Il) from an ammonia solution containing cobalt(Il) and cobalt(Ill) (15). 

Ziegler-type catalysts obtained from an organic acid salt or acetylacetone salt of nickel, cobalt, iron, or chromium which reacts with a reducing agent such as an organic aluminum compound. 

Rhodium acetylacetonate differed considerably from the other metal chelates in the acetylation reaction (26). Under the same conditions that had given extensive acetylation of the cobalt and chromium acetylacetonates, the rhodium chelate reacted very slowly and formed only a small amount of the monoacetylated compound (XX). Fortunately, the hydrolytic stability of rhodium acetylacetonate is such that the Friedel-Crafts reaction can be carried out under vigorous conditions that would rapidly degrade the chromium and cobalt chelates. Thus treatment of rhodium acetylacetonate with acetyl chloride and aluminum chloride in dichloroethane afforded the mono- and diacetylated chelates (XX and XXI). No triacetylated chelate was isolated from this reaction. In a similar manner butyryl-and benzoyl-substituted rhodium chelates (XXIII and XXIV) have been prepared. These and other experiments indicate that the rhodium acetylacetonate ring is less reactive than the cobalt or chromium rings. 

In Fig. 11 is plotted the angular dependence of the resonant magnetic field for chromium(lll) acetylacetonate in a single crystal of the cobalt(III) compound. This system has hv0 D for an -band spectrometer. The orientation of the crystal was that of orientation II in Fig. 6, in which the magnetic field is in the plane defined by the threefold symmetry axes of the two molecules in the unit cell. The angle given in Fig. 11 is the angle between... 

In the above examples, the nucleophilic role of the metal complex only comes after the formation of a suitable complex as a consequence of the electron-withdrawing effect of the metal. Perhaps the most impressive series of examples of nucleophilic behaviour of complexes is demonstrated by the p-diketone metal complexes. Such complexes undergo many reactions typical of the electrophilic substitution reactions of aromatic compounds. As a result of the lability of these complexes towards acids, care is required when selecting reaction conditions. Despite this restriction, a wide variety of reactions has been shown to occur with numerous p-diketone complexes, especially of chromium(III), cobalt(III) and rhodium(III), but also in certain cases with complexes of beryllium(II), copper(II), iron(III), aluminum(III) and europium(III). Most work has been carried out by Collman and his coworkers and the results have been reviewed.4-29 A brief summary of results is relevant here and the essential reaction is shown in equation (13). It has been clearly demonstrated that reaction does not involve any dissociation, by bromination of the chromium(III) complex in the presence of radioactive acetylacetone. Furthermore, reactions of optically active... 

In view of the difficulties encountered using Iron(III) acetylacetonate, attention was turned to the cobalt analogue. This compound was known to show some catalytic activity. Furthermore, a simple preparative procedure Is available which seems to give a well-defined crystalline product which Is reproducible from batch to batch, both as regards appearance and catalytic ability. For this reason, a detailed Investigation of systems containing this Initiator has been undertaken as, in effect, a "model" for aqueous-phase diene polymerisations using this class of Initiator. 

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